This Application claims priority to Taiwan Patent Application Serial No. 091210894 filed on Jul. 17, 2002.
The present invention relates to a button apparatus, and more specifically, to a button apparatus for a personal digital assistant (PDA).
As electronic technology progresses, the size of the many electrical devices can be made smaller and smaller. Consumers also love the electrical devices of small size without sacrificing the original functions because they are easy to carry and dispose. To catch up with the general trend, approach of size reduction of the button apparatus for an electrical device is rapidly followed by designers. Accordingly, there are many kinds of button apparatuses of small size coming to the market now.
Taking a PDA as an example, a PDA does not provide a conventional keyboard or a mouse in it for the mobile convenience. Instead, a stylus and few buttons are provided to control the cursor movement on the screen. A user is able to manipulate information or store data by using the stylus and the buttons. In general, most PDAs utilize a single direction button to control upward, downward, leftward, or rightward movement of a cursor.
Since a PDA is forced to reduce the size for commercial and practical consideration, the size of the direction button on a PDA is inevitably forced to reduce as well. However, size over-reduction of the direction button results in drawbacks, e.g. uncomfortable feeling of use, imprecise data input, slow input operation, and especially accidental erroneous actuation. Accidental erroneous actuation not only decreases the efficiency of cursor movement, but also wastes power. Therefore, the PDA of a small direction button is not very popular to consumers due to those drawbacks.
Moreover, the functions of a PDA greatly enhance nowadays by advanced technology. The function enhancement makes the number of the buttons on a PDA growing and also requires each button be capable of executing more functions. For example, the Enter function has been implanted into the traditional direction button in which drives the cursor upward, downward, leftward, or rightward. The probability of accidental erroneous actuation will increase for the type of PDA having small button of many functions. Therefore, the idea of implementing many functions within single button places restriction on size reduction trend of buttons.
Accidental erroneous actuation might occur when a user puts a PDA in a pocket or in a briefcase. Once the PDA is turned on due to accidental erroneous actuation, it consumes power of the battery and, furthermore, might damage data stored in the PDA at the worst case.
To satisfy consumers"" requirements, the kind of PDA, which provides a small button apparatus capable of avoiding accidental erroneous actuation is desired.
The present invention provides a button apparatus for an electrical device which has a circuit board. The circuit board includes M switch devices wherein M is a positive integer number.
The button apparatus of the present invention includes a body and a pillar. The body has M protrusions respectively corresponding to the M switch devices for selectively actuating the M switch devices. The pillar includes a first end and a second end. The second end has a projection used as a pivot. The first end presses against a central part of the body.
When the body is pushed downward, the body presses upon the first end and the projection touches against the circuit board in order to control one of the M protrusions to selectively actuate the very corresponding switch device.
The further aspects and advantages of the present invention will be clearly disclosed by the following detailed description and the attached figures.